14 files declare their use of PageVariant in Page Manager 8

FrontPageTest.php in src/Tests/FrontPageTest.php

PageConfigSchemaTest.php in src/Tests/PageConfigSchemaTest.php

Contains \Drupal\page_manager\Tests\PageConfigSchemaTest.

PageManagerAdminTest.php in page_manager_ui/src/Tests/PageManagerAdminTest.php

Contains \Drupal\page_manager_ui\Tests\PageManagerAdminTest.

PageManagerConfigTranslationTest.php in src/Tests/PageManagerConfigTranslationTest.php

Contains \Drupal\page_manager\Tests\PageManagerConfigTranslationTest.

PageManagerRoutingTest.php in tests/src/Kernel/PageManagerRoutingTest.php

PageManagerTranslationIntegrationTest.php in src/Tests/PageManagerTranslationIntegrationTest.php

Contains \Drupal\page_manager\Tests\PageManagerTranslationIntegrationTest.

PageNodeAccessTest.php in src/Tests/PageNodeAccessTest.php

Contains \Drupal\page_manager\Tests\PageNodeAccessTest.

PageNodeSelectionTest.php in src/Tests/PageNodeSelectionTest.php

Contains \Drupal\page_manager\Tests\PageNodeSelectionTest.

PagePlaceholderTest.php in src/Tests/PagePlaceholderTest.php

Contains \Drupal\page_manager\Tests\PageNodeSelectionTest.

PageReorderVariantsForm.php in page_manager_ui/src/Form/PageReorderVariantsForm.php

Contains Drupal\page_manager_ui\Form\PageReorderVariantsForm.

PageVariantAddForm.php in page_manager_ui/src/Form/PageVariantAddForm.php

Contains Drupal\page_manager_ui\Form\PageVariantAddForm.

PageVariantPageEntityTest.php in tests/src/Kernel/PageVariantPageEntityTest.php

Contains \Drupal\Tests\page_manager\Kernel\PageVariantPageEntityTest.

PageVariantTest.php in tests/src/Unit/PageVariantTest.php

Contains \Drupal\Tests\page_manager\Unit\PageVariantTest.

SerializationTest.php in tests/src/Kernel/SerializationTest.php

Contains \Drupal\Tests\page_manager\Kernel\SerializationTest.